White Lithium Grease (10g) and 2x O-rings for Nerf Elite Blasters O-rings are essential in maintaining the air seal in your blaster. Over time, they can wear out and deteriorate, allowing air to escape the plunger and dramatically reducing range and muzzle velocity. Occasionally replacing the o-rings in your blaster will help keep it consistent in range and power. If your blaster isnt priming as easily as youd like, a touch of white lithium grease applied to your moving parts helps smooth the action. These come in 10 gram packages, more than enough to keep your armory operating at peak performance. Remember to use the small plastic spike built into the cap to puncture the packets seal. With this package, you'll receive 2x Nerf Elite O-rings (including one large ring and one small ring that will fit the Elite blasters below) and 1 10 gram tube of White lithium grease. O-Rings are Compatible With: Retaliator, Elite Alpha Trooper, Rampage, Strongarm, and Firestrike. Blaster not included.